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I In Cardano's formula...

  1. Nov 10, 2016 #1
    in Cardano's cubic formula. when reducing a cubic to its depressed form: from ax^3 + bx^2 + cx + d = 0 to a form like y^3 +py + q = 0. what is the motivation behind making x = y - b/3a first before proceeding to depress the cubic? what was cardano's motivation for that substitution or whoever showed him that technique?
     
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  3. Nov 10, 2016 #2

    micromass

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  4. Nov 10, 2016 #3
    Last edited: Nov 10, 2016
  5. Nov 10, 2016 #4

    micromass

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    That was a hint: think about inflection points. I'll leave the rest to you
     
  6. Nov 11, 2016 #5
    okay i'll think about it first
     
  7. Nov 11, 2016 #6
    so i noticed that inflection points is equal to -b/3a but i'm not sure if that meant anything at all. still thinking and researching
     
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